Answer:
jim is correct, x does equal 7°. justify your answer by putting seven back into the equation. it gives you back that 180 equals 180, therefore it is correct
Step-by-step explanation:
so, all angles of a triangle have to add up to 180;
(15x) + (8x - 11) + (3x + 9) = 180
15x + 8x - 11 + 3x + 9 = 180
add your common numbers
26x - 2 = 180
add 2
26x = 182
divide 26
x = 7
put it back into the equation
15(7) + 8(7) - 11 + 3(7) + 9 = 180
180 = 180
